Mercuric reductase is an essential component in the mercury detoxification in a number of bacteria. It catalyzes the two-electron reduction from Hg(II) to Hg(0). The homo-dimeric protein requires NADPH and FAD for catalysis. In addition to these cofactors, four cysteine residues have been identified in the active site and shown to play a key role in mercury binding and reduction. One of the specific goals of my work is to define these two steps in molecular detail. So far the structural information available from x-ray crystallography and access through MidasPlus has proven very useful for the design of experiments as well as their interpretation.